The present invention relates to a combtooth assembly for an escalator combplate which is responsive to combplate obstructions and which can generate an alarm signal in response to an obstruction.
The riser and step tread surfaces of escalators are normally of a ribbed construction that provides, with respect to at least the tread in particular, a more secure contact surface for passengers. At the escalator landings the steps are engaged by, and pass under a combplate, which provides the landing platform on which the escalator""s users embark onto, or disembark from, the moving steps. The forward edge of the combplate is provided with a complementary serrated construction which closely interfits with the ribbed construction of the moving steps to form a smooth transition area.
The point of passage of the moving steps under the combplate creates a potential location for entrapment between the step and combplate. Aware of this potential, operating codes and regulations typically require that in the event of an obstruction, which generates an upward force upon the combplate of an excess of a particular level, escalator operation is shut down.
Obstructions resulting in forces below the shut-off level can occur, however, and can also be deleterious, either to escalator operation or to a passenger. It is accordingly a purpose of the present invention to provide a combplate force detector apparatus that is capable of detecting and responding to relatively low intensity forces, permitting an alarm indication to be registered.
Another purpose of the present invention is to provide a combplate force detector apparatus that utilizes a pivoting combteeth plate that can be easily installed and replaced by field personnel.
Still another purpose of the present invention is to provide a combplate force detector apparatus that is adjustable over a range of activation forces.
Yet a further purpose of the present invention is to provide a combplate force detector apparatus utilizes a pivoting combteeth plate wherein the range of motion of the pivoting element is limited to prevent further interference with escalator operation and passenger use.
In accordance with the foregoing and other objects and purposes, a combplate force detector in accordance with the present invention comprises a combplate construction having combteeth plates mounted to a main combplate assembly in a manner that allows them slight freedom to rotate upwardly in response to an obstruction. Rotation of a combtooth plate operates an electrical switch, by which the rotation and corresponding obstruction can be sensed. Stop means are provided to limit the degree of rotation of the combteeth plate to prevent the combteeth plate from rising above step level which would allow larger objects to become entrapped.